Portable infusion pump

ABSTRACT

The present invention relates to a medicament delivery device comprising a housing, a compartment inside said housing for positioning a medicament container, an injection needle arranged to said housing, being connectable to said medicament container for delivering a dose of medicament, a manually operated activation mechanism for activating said device, an actuation mechanism operably connected to said activation mechanism and arranged to, upon activation of said activation mechanism, extend said injection needle from a first position inside said housing to a second position wherein a penetration of a patient is performed, a plunger rod arranged in said housing capable of acting on said medicament container for delivering a dose of medicament through said injection needle, a driver capable of acting on said plunger rod for delivering a dose of medicament. The invention is characterised in that said device comprises a needle cover operably arranged in said housing from a first position inside said housing to a second extended position outside said housing for shielding said injection needle when said injection needle is in said second position.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/989,509, filed May 25, 2018, which is a continuation of U.S.patent application Ser. No. 15/031,582, filed Apr. 22, 2016, now U.S.Pat. No. 10,010,681, which is a U.S. National Phase Application pursuantto 35 U.S.C. § 371 of International Application No. PCT/EP2014/072655filed Oct. 22, 2014, which claims priority to Swedish Patent ApplicationNo. 1351259-5 filed Oct. 23, 2013. The entire disclosure contents ofthese applications are herewith incorporated by reference into thepresent application.

TECHNICAL AREA

The present invention relates to a medicament delivery device and inparticular a compact and easy to use infuser.

BACKGROUND

For a number of years infusers have been used that provides the patientor user with the means of administering a drug in an easy way withoutthe need for a medically trained person, such as a physician or nurse tohandle the device.

One drawback with these infusers is that they have a medicamentcontainer of a certain length as well as a plunger rod acting on saidmedicament container for delivering a dose of medicament, also having acertain length, whereby the total length of a device has to be at leastthe length of the medicament container and the plunger rod. If a drivemember is used, such as for instance a drive spring, the length of thedevice is further increased.

One way of handling this is to make at least the plunger rod shorter fornot adding so much to the overall length. One solution to this is tohave a flexible plunger rod, which is disclosed for example in EP 1 583573 where the plunger rod may be bent or formed as a circle. Anothersolution is disclosed in EP 1 276 529 having a bendable plunger rod witha ratchet on a side surface, where the plunger rod is bent around acogwheel, for driving the plunger rod.

The drawback with these solutions is that the length might not beincreased by the whole length of the plunger rod, but at least by someamount because the circle formed by the bent plunger rod also adds tothe length. Further, the dimensions of the device in other directionsare increased considerably by these solutions, providing a rather bulkydevice.

The above-mentioned solutions utilize some sort of power spring woundaround a shaft or the like positioned in the centre of the circle formedby the curved plunger rod. These power springs often act directly oralmost directly on the curved plunger rod, such as with the device of EP1 276 529 where the power spring acts on the cogwheel.

The drawback with this drive solution is that it complicates theaddition of functions such as activation mechanisms, constant injectionspeed mechanism, automatic stop mechanisms, just to mention a few. Thisis mainly because the plunger rod surrounds and thereby blocks access tothe plunger drive spring without enlarging the device.

Regarding the injection speed control aspect, some solutions have beendevised, such as for example in EP 1 326 659 where an electric motor isutilized for driving the flexible plunger rod. Also document WO2010/112377 discloses a device utilizing electric motors for driving andcontrolling the movement and speed of the plunger rod.

The drawback with this is that the device has to rely on electric powerin order to deliver a dose of medicament. If any batteries used aredepleted, the device cannot be used at all, which may be critical forsome types of drugs.

Another drawback with many of the mentioned devices is that there is nofeature or mechanism for handling the injection needle after completedinjection. When the device is withdrawn, the injection needle completelyexposed and may cause injuries to persons handling or coming in contactwith the device after use.

SUMMARY

In the present application, when the term “distal part/end” is used,this refers to the part/end of the device, or the parts/ends of themembers thereof, which under use of the device is located the furthestaway from the medicament delivery site of the patient. Correspondingly,when the term “proximal part/end” is used, this refers to the part/endof the device, or the parts/ends of the members thereof, which under useof the device is located closest to the medicament delivery site of thepatient.

The aim of the present invention is to remedy the drawbacks of the stateof the art medicament delivery devices. This aim is obtained with amedicament delivery device according to the features of the independentpatent claim. Preferable embodiments of the invention form the subjectof the dependent patent claims.

The medicament delivery device preferably comprises a housing having acompartment inside said housing for positioning a medicament container.The medicament container may have a number of designs that are suitablefor delivering a dose of medicament when the device is activated.According to one favourable aspect, the medicament container may bearranged with a stopper that is movable by appropriate means. Themedicament container may further be arranged with some connectioninterface to an injection needle, through which a dose of medicament maybe delivered. The connection interface may for example be a septum orother type of membrane or wall that may be penetrated or pierced by aconnection element, which connection element may be a pointed end of aconduit in flow communication with the injection needle.

The device may further advantageously comprise a manually operatedactivation mechanism for activating said device in order to deliver adose of medicament. The activation mechanism may be operably connectedto a number of functions and features of the device.

One such feature may be an actuation mechanism arranged to, uponactivation of said activation mechanism, extend the injection needlefrom a first position inside said housing to a second position wherein apenetration of a patient is performed. Thus, when the device is placedon the body of a patient and the activation mechanism is operated, apenetration of the skin of the patient will be performed by theactuation mechanism, rendering the device ready for delivering a dose ofmedicament.

In order to provide a dose of medicament from the medicament containerthrough the conduit to the injection needle, the device is preferablyprovided with a plunger rod in said housing and arranged to act on thestopper of the medicament container. In order to do so, the plunger rodmay be operably connected to a driver capable of acting on said plungerrod for delivering a dose of medicament. In this aspect, the driver mayadvantageously comprise some energy accumulating feature, which energymay drive the plunger rod. The energy accumulating feature may comprisea number of different designs such as compression springs, torsionsprings, clock springs, gas springs and the like, just to mention a few.

Preferably the device may comprises a needle cover operably arranged insaid housing from a first position inside said housing to a secondextended position outside said housing for shielding said injectionneedle when said injection needle is in said second position. With thissolution, the injection needle may be protected when the device isremoved from the body of the patient, thereby minimizing the risk ofunintentional needle sticks.

According to one feasible solution, the actuation mechanism may comprisea locking mechanism capable of locking said injection needle in saidsecond position. This ensures that the penetration depth of theinjection needle is maintained during the subsequent injection sequence.Thus, it is not required for the user to operate the activationmechanism after the injection needle has reached the second penetrationposition.

Further, another favourable feature, the needle cover may compriselocking elements operably arranged to lock said needle cover in saidsecond position. This further minimizes the risk of injuries of theinjection needle since the needle cover is locked from movement.

According to another favourable feature, the activation mechanism maycomprise two operating elements placed on opposite sides of said device.This solution of the activation of the device is advantageous since theoperating elements may be operated by one hand of the user gripping thedevice. According to a further favourable solution, the operatingelements may comprise activation buttons, which buttons are manuallydepressed for activating said device. Since the buttons are placed onopposite sides of the device, the forces for depressing the buttons aredirected towards each other. Thus the forces will not affect theposition of the device on the body of the patient, which is an advantageduring the penetration and the injection sequence, because any movementof the device when the injection needle has penetrated the body willcause pain and discomfort.

According to one feasible solution, the activation buttons may beconnected to said injection needle via a linkage comprised in saidactuation mechanism, thereby enabling movement of said injection needleto said extended position when said buttons are depressed. The linkagethus enables movement of the injection needle in directions deviatingfrom the movement directions of the activation buttons, for example adirection ninety degrees in relation to the activation buttons. Whenusing a linkage, the locking mechanism of said injection needle maypreferably be comprised in the linkage.

In order to ascertain a smooth and more or less constant injectionspeed, the device may further comprise an injection speed controlmechanism operatively connected to said driver. With such a mechanism,the injection speed may be chosen and controlled in a positive manner.This may be an important feature for medicament solutions that forexample are painful when delivered in larger quantities quickly. Thedose delivery may then be set and controlled to deliver very smallquantities continuously for longer time periods.

According to one feasible solution, the injection speed controlmechanism may for example comprise a pallet fork acting on an escapementwheel, as well as a transmission between said drive means and saidescapement wheel. This solution provides possibilities of a choosing andchanging injection speeds in a wide range. The use of a transmissionenables the choice of gearing those suites the delivery speed of acertain medicament. In order to provide a certain injection speed, theescapement wheel is preferably drivably connected to a drive spring.

According to another preferable solution, the device may furthercomprise an auto-stop mechanism capable of permanently stopping saidinjection speed control mechanism at the end of a dose deliverysequence. Thereby it is clearly indicated to a user that the injectionis completed and that the device may be removed from the patient.

To further enhance the usability of the device, it may further comprisea manually operable stop mechanism capable of permanently stopping saidinjection speed control mechanism upon activation. This may for examplebe an advantage in a situation when the user for some reason has toremove the device from the body. The stop mechanism will then ascertainthat no medicament is expelled from the device after removal.

According to another feasible solution, the device may further comprisea manually operated pausing mechanism capable of temporarily stoppingand subsequent starting of the injection speed control mechanism uponactivation. This may for example be an advantage when the user hasstarted the injection sequence but wants to pause it for some reason.The injection speed control mechanism is then stopped only temporary andmay be resumed by the user. The pausing mechanism may for example byoperably connected to the activation mechanism.

According to another feasible solution, the device may also comprise amedicament container penetration mechanism operably connected to saidactivation mechanism for creating, upon activation, a communicationbetween the medicament inside said medicament container and saidinjection needle. In this manner, the content of the medicamentcontainer is not affected in any way before the device is activated.Thus, the medicament container may be inserted into the device at anytime without the risk of degrading the medicament, because a passagebetween the interior of the medicament container and the injectionneedle is only obtained after activation of the device.

These and other aspects of, and advantages with, the present inventionwill become apparent from the following detailed description of theinvention and from the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

In the following detailed description of the invention, reference willbe made to the accompanying drawings, of which

FIG. 1 is a perspective view of an embodiment of a medicament deliverydevice,

FIG. 2 is a perspective view of the device of FIG. 1 turned 180 degrees,

FIG. 3 is a perspective view of the device of FIG. 1 with a housing partremoved,

FIG. 4 is a perspective view of the device of FIG. 1 turned 180 degreesin relation to FIG. 3 and with a housing part removed,

FIGS. 5-7 are detailed views of components and mechanisms comprised inthe device of FIG. 1,

FIGS. 8a and 8b show two different views of the same specific componentsand mechanisms of the device of FIG. 1;

FIG. 9 illustrates detailed views of components and mechanisms comprisedin the device of FIG. 1;

FIGS. 10a and 10b show two different views of the same component of thedevice of FIG. 1;

FIGS. 11-17 show detailed views of components and mechanisms comprisedin the device of FIG. 1;

FIGS. 18a and 18b show two different views of the same specificcomponents and mechanisms of the device of FIG. 1;

FIGS. 19-28 show different functional positions of the device duringuse.

DETAILED DESCRIPTION

The embodiment of a medicament delivery device shown in the drawingscomprises a housing, which may be in two housing parts 10, 12, FIGS. 1and 2. It is of course feasible that it comprises more than two housingparts. Preferably, the complete housing has a generally rectangularshape having a measure or thickness as seen along a proximal-distal axis14 that is much less than the dimensions in the other two directions,vertical 16 and horizontal 18. The housing is arranged with operatingelements, 20 a, b in the embodiment shown, FIGS. 1 and 2, as two buttonsarranged on opposite side surfaces of the device.

The device is arranged with a driver 50, the function of which will beexplained below. The driver comprises a shaft 24, FIG. 5, which shaft isrotatably arranged inside the housing and journalled with a distal endin a seat 26, FIG. 6, on the inner surface of the distal housing part12. An Allen keyhole 22 is arranged on an end surface of a shaft 24,where the Allen keyhole 22 is accessible via an opening on theproximally directed housing surface, FIG. 2. A proximal end of the shaft24 is arranged with a number of arms 28, FIG. 5, that extend in agenerally circumferential direction. The free ends of the arms 28 arearranged with radially outwardly directed edges 30. The proximal end ofthe shaft 24 with the arms 28 is intended to fit into a seat 32, FIG. 7,on the inner surface of the proximal housing part 10. The seat 32 issurrounded by an annular ledge 34 having radially inwardly directedteeth 36 of a certain configuration. The teeth 36 are intended tocooperate with the free ends of the arms 28 as will be described.

The driver 50 further comprises a flat spiral clock spring 38, FIG. 5,wound around the shaft 24, wherein an inner end of the spiral clockspring 38 is attached to the shaft 24. The spring 38 is further arrangedinside a spring housing 40, FIG. 5, designed as a generally tubularpart. An outer end of the spiral clock spring 38 is attached to an innersurface of the spring housing 40. The spring housing 40 is furtherarranged with a sidewall 42, FIG. 5, having a central opening 44,through which the shaft 24 can extend. On the outer circumferentialsurface of the spring housing 40 a ratchet 46 is arranged, FIG. 5. Theratchet 46 is intended to cooperate with a cogwheel 48 of the driver 50,FIG. 8. The driver 50 further comprises a shaft 52 where the cogwheel 48is attached to one end such that the shaft 52 extends generally in theradial direction of the spring housing 40 as seen in FIG. 8 along line53. The shaft 52 of the driver 50 is journalled in the proximal housingpart 10 by support elements 54, FIG. 7. A second cogwheel 56, FIG. 8b ,is attached to the second end of the shaft 52, having a generallyconical shape. The second cogwheel 56 is arranged to be in contact withteeth of a third mating cogwheel 58. The third mating cogwheel 58 isjournalled on a shaft 60 having an extension generally perpendicular tothe extension of the shaft 52. Attached to the third mating cogwheel 58,or made integral with, is a drive wheel 61 having teeth 62 around itscircumference. These teeth 62 are arranged to cooperate withcorresponding teeth 64 on a plunger rod 66, FIG. 4.

In the embodiment shown the plunger rod 66 is of a certainconfiguration, FIGS. 9 and 10. The plunger rod 66 generally has arectangular configuration as seen in a cross-sectional view. Further theplunger rod 66 is divided up into a number of plunger rod segments. Theend of the first plunger rod segment 68 that is to be in contact with astopper 69 of a medicament container 70, FIG. 4, is arranged with agenerally circular pusher plate 72, FIG. 9, having a diameter somewhatless than the inner diameter of the medicament container 70. The firstplunger rod segment 68 has a certain length. The following plunger rodsegments 74, FIG. 9, are somewhat shorter. All plunger rod segments 74are arranged with connection elements that comprise generally verticallyarranged cut-outs 76 at their distal ends, FIG. 10. The sidewalls of thecut-outs 76 are arranged with generally vertically directed grooves 78,FIG. 10, having a certain configuration. Further, each plunger rodsegment apart from the first segment, is arranged with a proximallydirected nose 80 designed to fit into the cut-out 76 of a previousplunger segment 68. Further the nose 80 is arranged with generallyvertically extending ledges 82 having similar configuration as thegrooves 78 of the cut-out 76, whereby the ledges 82 may fit into thegrooves 78. Further, the cut-outs 76 are arranged with flexible tongues84, FIG. 10b that engage a surface of the nose 80 of a subsequentplunger rod segment so as to lock the segments to each other.

The plunger rod segments 74 are arranged in a generally vertical stackon top of each other and directed such that the nose 80 of the segmentspoint in the same direction, FIGS. 8a and 9. The stack of plunger rodsegments is held in place inside the housing by a magazine 86, FIG. 9providing side supports on three sides. The fourth side is arranged withan elongated slit 88, FIG. 9. In the slit 88 a flat band spring 90 isarranged having a first upper end attached to a fixture post 92 on theproximal housing part 10, FIGS. 4 and 7. The second lower end of theband spring 90 is arranged with a coil 94, FIG. 9, which coil 94 fitsinto a cavity 96 attached to a plunger rod follower 98 positioned insidethe magazine 86, FIG. 9. The function of the described components willbe explained below.

The proximal end of the plunger rod 66 extends into a space in thedevice intended to accommodate the medicament container 70, FIG. 4. Thespace is accessible via a hingedly attached lid 100, FIGS. 1 and 4, onan upper area of the housing. Inside the space a holder or cartridgeretainer 102, FIGS. 3 and 4, is arranged, on which the medicamentcontainer 70 may be placed. In that respect, the cartridge retainer isarranged with a holding portion 104, FIG. 4, in which a neck portion105, FIG. 11, of the medicament container 70 fits. A penetrationmechanism 106 is further arranged in the device. It comprises acup-shaped element 108, FIG. 11, arranged slidable in relation to theholding portion 104 and thus the neck portion 105 of the medicamentcontainer as seen in a longitudinal direction thereof. The cup-shapedelement 108 is arranged with a hollow needle or a hollow pointed spike110 directed towards the neck of the medicament container, FIG. 11,intended for piercing a septum 112 of the neck portion 105 of themedicament container 70.

Further, an end surface of the cup-shaped element 108 is arranged with aledge 114 having an inclined surface 116, FIG. 12. The ledge 114 isintended to interact with a pusher 118 of the penetration mechanism. Thepusher 118 is designed as a generally elongated rod 120 provided with aninclined surface 122, FIG. 12, arranged to be in contact with theinclined surface 116 of the cup-shaped element 108. The pusher 118 isfurther arranged with a compression spring 124 arranged surrounding therod 120 and fitted between a generally radially directed ledge 126 ofthe rod and a seat 128 in the housing parts as seen in FIG. 7. Further,in an initial position as seen in FIG. 12, the pusher 118 with itsinclined surface 122 is somewhat turned in relation to the inclinedsurface 116 of the cup-shaped element 108. In this position, the ledge126 fits into a recess 127 in the seat 128, FIG. 7, thereby locking thepusher with spring 124 compressed. Further, a generally radiallyextending protrusion 132 is arranged on the rod of the pusher, below asurface area 131 on the side of the pusher 118, FIG. 12.

The device is further arranged with an activation mechanism 129, FIG.13. It comprises the two operating elements 20 a and 20 b that in theembodiment shown are arranged as push buttons. The push button 20 a isarranged with a protrusion 130 on its side surface, FIG. 12. Thisprotrusion 130 is intended to interact with the surface area 131 as willbe explained below. Further, the protrusion 130 is positioned such inrelation to the protrusion 132 of the pusher that any movement of thepusher in the vertical direction is prevented even if the ledge 126would unintentionally be moved out of the seat 128, which might occur ifthe device was shaken or dropped on a hard surface.

Each push button 20 a, b, is arranged with a generally U-shaped guideelement 134, FIGS. 4 and 13, where the free ends of the U's of the guideelements 134 are arranged with inwardly directed ledges 136, FIG. 14.These guide elements 134 are intended to interact with guide rails 138,FIG. 6, on an inner surface of the distal housing part 12. The guiderails 138 are arranged with a generally T-shaped cross section as seenin FIG. 14.

Further, one of the push buttons 20 b is arranged with an elongated rod140, FIG. 13. The end of the elongated rod 140 is arranged with agenerally cylindrical body 142. The cylindrical body 142 is designed tofit into a tubular body 144, which also is attached to an elongated rod146. The elongated rod 146 is journalled in a post 147 of the other pushbutton 20 a, FIG. 13, so as to allow rotational movement of theelongated rod 146 and the tubular body 144 in relation to the pushbutton 20 a.

The cylindrical body 142 is further arranged with a ridge 148 extendingin the longitudinal direction of the cylindrical body 142. The ridge 148fits into a slit 150 in the tubular body 144, such that the bodies 142,144 are rotationally locked to each other while allowing longitudinalmovement between them. A compression spring 149, FIGS. 13 and 15, isarranged inside the tubular body 144 acting between an end wall 152 ofthe tubular body 144 and an end wall 154 of the cylindrical body 142.The cylindrical body is further arranged with grooves 156, FIGS. 15 and16, having a certain configuration as will be described. A guide element158, FIGS. 13 and 17, is arranged to be placed in the grooves with a pin160. The pin 160 is attached to a generally T-shaped body 162, whichbody 162 fits into a slit 164 in the tubular body, which slit 164 isarranged generally perpendicular to the longitudinal direction of thetubular body 144, as seen in FIG. 13. These components form a pausingmechanism, as will be described.

An actuation mechanism 165, FIG. 18, is further arranged to theactivation mechanism. The actuation mechanism 165 comprises twoelongated guide rods 166, FIG. 18, arranged slidable on the guide rails138, FIG. 6. In that respect, the guide rods 166 preferably have thesame shape as the guide elements 134 when seen in a cross-section. Eachguide rod 166 is arranged with a ledge 168, FIG. 18a , extendinggenerally transversal to the longitudinal direction of the guide rod166. Each ledge 168 is designed to cooperate with a generally L-shapedholding element 170, FIG. 6, where the free end is arranged with a ledge172 arranged to grip the transversal ledge 168 of the guide rod 166 aswill be described.

A linkage 167 is comprised in the actuation mechanism, FIG. 18, whereineach guide rod 166 is further arranged with a first attachment post 174comprising a bearing passage. A bearing shaft of an actuator arm 176 isjournalled in the first attachment post 174. The opposite end of theactuator arm 176 is provided with a bearing shaft intended to fit into abearing passage of a second attachment post 178. The second attachmentpost 178 is in turn attached to an arm 180 of a needle holder 182. Theneedle holder 182 is designed with a generally cylindrical outer shape.The needle holder is arranged with a central passage through which aninjection needle 184 is extending. Further, a tube 186 is attached toone end of the injection needle 184, FIG. 11. The tube 186 then connectsto the spike 110, thereby providing a passage between the spike 110 andthe injection needle 184.

A needle cover 188 is further arranged to the device, FIGS. 3 and 7. Itcomprises a generally tubular body having a number of longitudinallyextending ribs 190 on its outer surface, FIG. 7, in the embodiment showntwo ribs 190 arranged on opposite sides of the needle cover 188. Theribs 190 end a short distance from a proximal end wall 192, FIG. 3, ofthe needle cover 188, which distance generally corresponds to thethickness of the proximal housing part 10. This is due to that theproximal end of the needle cover protrudes through a passage 194 in theproximal housing part, FIG. 7, where proximal end surfaces of the ribs190 abut the inner surface of the proximal housing part 10 adjacent thepassage 194.

The passage 194 is further arranged with cut-outs 196, FIG. 7, havinggenerally the same shape as the ribs 190 in a cross-sectional view. Theproximal end wall 192 of the needle cover 188 is further arranged with acentral passage 198, FIGS. 3 and 19, which central passage 198 issurrounded by a generally tubular element 200, FIGS. 7 and 19, extendingin the distal direction. The tubular element 200 has a diameter somewhatlarger than the outer diameter of the needle holder 182, where thelatter is able to slide inside the tubular part along theproximal-distal axis 14. The tubular element 200 is further arrangedwith two slits 202, FIG. 7, in which the arms 180 of the needle holder182 may be positioned.

Further the needle cover 188 is also arranged with slits 204, with afirst part 204 a open in the distal direction, where the first part 204a transforms into a second generally circumferential second part 204 b,which in turn transforms into a third part 204 c generally parallel withthe first part 204 a but closed in the distal end. The needle cover 188is further arranged with radially outwardly extending ledges 206, FIG.7, one on each side of the needle cover 188 as seen in the transversaldirection. Further, a longitudinally extending ledge 207, FIG. 7 isprovided in the distal end surface of the needle cover 188. Arms 208 arefurther arranged on the inner surface of the proximal housing partsurrounding the passage extending in the distal direction, FIG. 7. Thesearms are arranged with radially inwardly extending ledges 210. Further,a needle cover spring 211, FIG. 19, is arranged between the innersurface of the end wall 192 of the needle cover 188 and the arms 180 ofthe needle holder 182. Also, a needle cap 209, FIG. 2, is releasiblyarranged in the central passage 198 of the needle cover 188, surroundingthe needle and keeping it sterile.

The device is further arranged with an injection speed control mechanism212, FIG. 8, that preferably is capable of providing a constantinjection speed during the injection. It comprises a transmission 213,FIGS. 8a and 8b , with a first cogwheel 214, FIG. 8b , acting on theratchet 46 on the outer surface of the spring housing 40, where thefirst cogwheel 214 has a smaller diameter than the ratchet 46. The firstcogwheel 214 is attached to a second cogwheel 216 having a diametergenerally corresponding to the first cogwheel but with a larger numberof teeth, wherein the first and second cogwheels 214, 216 are rotatablyarranged to a first shaft 218. The second cogwheel 216 is in engagementwith a third cogwheel 220 having a smaller diameter. The third cogwheel220 is attached to a fourth cogwheel 222 having a larger diameter. Thethird and the fourth cogwheel 220, 222 are rotatably arranged to asecond shaft 224.

The fourth cogwheel 222 is then in engagement with a fifth cogwheel 226having a smaller diameter. The fifth cogwheel 226 is attached to a sixthcogwheel 228 having a larger diameter. The fifth and the sixth cogwheels226, 228 are rotatably arranged to a third shaft 230. The sixth cogwheel228 is in engagement with a seventh cogwheel 232. The seventh cogwheel232 is attached to an eighth cogwheel 234. The seventh and eighthcogwheels 232, 234 are arranged on a fourth shaft 236. The eighthcogwheel 234 is in engagement with a ninth cogwheel 238. The ninthcogwheel is attached to an escapement wheel 240 having a number ofteeth. The ninth cogwheel 238 and the escapement wheel 240 are arrangedon a fifth shaft 241.

A pallet fork 242 is arranged rotatable on a shaft 244 where the arms ofthe fork are arranged to act on the teeth of the escapement wheel 240.Further an arm 246 is arranged to the pallet fork 242 where the free endof the arm 246 is arranged with two fingers 248. These fingers are inengagement with a protrusion 250 attached on a side surface of aregulator wheel 252. One end of a balance spring 254 is attached to theregulator wheel 252 and the other end of the balance spring 254 isattached to a housing part of the device, capable of oscillating saidregulator wheel when activated.

The outer circumferential surface of the regulator wheel 252 is arrangedwith indentations 256. The protrusion 250 of the regulator wheel 252 ispositioned such in relation to the fingers 248 that oscillation of theregulator wheel 252 will cause the pallet fork 242 to swing back andforth. A more detailed function will follow below. A locking element 258in the form of an arm attached to the push button 20 a, FIGS. 3 and 13,is arranged to fit into the indentations 256 in an initial position ofthe push button 20 a, as will be explained below.

The device is further arranged with an auto-stop mechanism 260, FIG. 20.It comprises a beam 262 arranged with a shaft 264 journalled in a post266 on an inner surface of the proximal housing part 10, FIG. 7. Theshaft 264 is positioned generally midway along the longitudinaldirection of the beam, producing two oppositely directed first andsecond arms 268 a, 268 b. An end of the first arm 268 a is arranged tobe in contact with one of the ledges 206 on the needle cover 188, asseen in FIG. 20. A torsion spring 270 is further wound around the post266 and is attached with one free end 272 a to the second arm 268 b ofthe beam. The other free end 272 b of the torsion spring 270 is attachedto a fixed housing part, in the embodiment shown the cartridge retainer102. The second arm 268 b extends through an opening 274 in the magazine86, FIG. 4, having a free end that is in contact with and pushes againstthe plunger rod segments 74 due to the force of the torsion spring 270,as seen in FIG. 20.

The device is further arranged with a manually operated stop mechanism276, FIG. 21. It comprises an actuator element 278 in the form of abutton that is accessible via an opening 280 in the distal housing part,FIG. 6. The actuator element 278 is arranged with an arm 282 having agenerally U-shaped form as seen in cross-section. The free ends of the Uare arranged with inwardly directed ledges. A guide post 284, FIG. 6,attached to the inner surface of the distal housing part, is arranged tofit inside the U-shaped arm, providing guiding action of the stopmechanism when moved linearly as will be described. The stop mechanism276 further comprises a beam 286 FIG. 21, directed generally transversalto the arm 282. In an initial position of the stop mechanism, an uppersurface of the arm 282 is in contact with the ledge 207 of the needlecover 188 as seen in FIG. 21.

Intended Function of the Device

The device is usually delivered without a medicament container. Thus,before use, a medicament container 70 has to be inserted into thedevice. The lid 100 at the upper end of the device is then opened,whereby the space and the cartridge retainer 102 are accessible. Themedicament container 70 is then inserted with a neck portion towards theholding portion 104 of the cartridge retainer 102. The lid is thenclosed.

The device is now made ready. This may be done by inserting an Allen keyinto the hole 22 on the proximal surface of the device and turning theshaft 24 in the clockwise direction. This in turn causes the arms 28 toslide over the teeth 36 because of the direction of the arms in relationto the teeth. Because the inner end of the spiral clock spring 38 isattached to the turning shaft 24 the spiral clock spring 38 istensioned. When the user stops turning the shaft 24, it is lockedagainst rotating back because of the edges 30 of the arms 28 now lockingagainst the teeth 36. Also, after activation of the device, the shaft 24cannot be rotated again. The device is now ready for delivering a doseof medicament.

In the initial position, the operating elements, the activation buttons20 a, 20 b, are in their extended position as seen in FIGS. 3 and 4. Inthis position, the locking element 258 is in engagement with theregulator wheel 252, as seen in FIG. 3, whereby action of the constantspeed control mechanism 144 is prevented. The balance spring 254 hasbeen tensioned beforehand. The process up to this point may be donewithout the device being in contact with the patient. In order to beable to deliver a dose of medicament to the patient, the needle cap 209is removed from the central passage 198 of the needle cover 188 and theproximal surface of the device has to be in contact with some part ofthe body of the patient, i.e. to releasibly attach the device to thebody. This may be performed in many ways, by straps, by merely pressingit manually, but preferably the proximal surface is arranged with somesort of adhesive, like sticky tape, with which the device may befastened to the body. One variant is to have double-sided sticky tape onthe proximal surface with an outer protective layer that is peeled offbefore attachment.

Activation of the Device

When the device is to be activated, the user presses both activationbuttons 20 a, 20 b towards each other. This causes several things to beinitiated.

1. Connection of Medicament Container

When the activation button 20 a is moved inwards, the protrusion 130 onthe activation button is moved along the surface area 131 of the pusher,thereby turning the latter around its longitudinal axis. This causes theledge 126 to be moved out of the locking engagement with the recess 127out of contact with the protrusion 132 of the penetration mechanism.Also the protrusion 130 is moved away from the protrusions 132 of thepusher. Thus, the pusher 118 is released and is forced upwards due tothe compression spring 124, FIG. 22. This causes the inclined surface122 of the pusher 118 to be moved in contact with the inclined surface116 of the ledge 114 of the cup-shaped element 108 such that cup-shapedelement 108 and the spike 110 is moved towards the neck of themedicament container, which in turn causes the end of the spike 110 topenetrate the septum 112, creating a passage between the interior of themedicament container and the injection needle via the tube 186.

2. Penetration of Patient

The inwards pressing of the activation buttons causes the guide elements134 to move inwards along the guide rails 138. The guide elements 134will thereby also move the guide rods 166 inwards, FIG. 23. Due to theattachment of the needle holder 182 with the guide rods 166 via theactuator arms 176, the needle holder 182 with its injection needle 184will move in the proximal direction whereby the injection needle 184will extend in the proximal direction beyond the surface of the proximalhousing part, causing a penetration of the patient. The advancement ofthe needle holder 182 with its arms 180 will compress the needle coverspring 211, as seen in FIG. 23. When the guide rods 166 have advancedinwards a certain distance inwards, the ledges 168 of the guide rods 166will pass the ledges 172 of the holding elements 170. This prevents theguide rods 166 from moving back outwards, and holds thus the needleholder with the injection needle in the extended position as seen inFIG. 23.

Also, when the activation buttons are pressed inwards, the cylindricalbody 142 will move inside the tubular body 144, compressing the spring149. The pin 160 of the guide element 158 will move in the grooves 156on the outer surface of the cylindrical body as seen in FIG. 16 from astart position I. When the pin 160 reaches position II and follows theinclined surface of the groove to position III, the body 162 of theguide element will move in the slit 164. In this position, theactivation buttons are in their most depressed position and theinjection needle has penetrated the patient, who may now release thebuttons. This will cause the pin 160 to move to position IV, keeping theactivation buttons in a rather depressed state.

3. Start of Injection

The inwards pressing of the activation buttons will also cause theinjection to start in that the locking element 258 of the activationbutton 20 a is moved out of contact with the indentations 256 of theregulator wheel 252, as seen in FIG. 22. The tensioned balance spring254 will now oscillate the regulator wheel 252, whereby the pallet fork242 will start to oscillate back and forth due to the contact with theprotrusions 250 on the regulator wheel.

This in turn will cause the escapement wheel 240 to move an increment orrotational angle per time unit, thus controlling the speed. Thisrotational speed is then transferred through the transmission 213 to thespring housing 40, determining the rotational speed of the springhousing 40. However, it is the spiral clock spring 40 that causes thespring housing 40 of the driver 50 to rotate, the transmission merelyregulates the rotational speed.

Injection Operation

The rotation of the spring housing 40 will cause its ratchet 46 to movearound the circumference, thereby acting on the cogwheel 48 of thedriver 50. Thus the shaft 52 will rotate as will the second conicalcogwheel 56. The rotation of the conical cogwheel 56 is transferred tothe third mating cogwheel and thus the drive wheel 61. Because the teeth62 of the drive wheel 61 are in engagement with the teeth 64 of thefirst plunger rod segment 68, the first plunger rod segment 68 is movedin the direction of the medicament container 70, whereby the pusherplate 72 acts on the stopper 69 in the medicament container 70. When thefirst plunger rod segment 68 has moved a distance towards and inside themedicament container 70, the space behind the first plunger rod segment68 is so large that a subsequent plunger rod segment 74 may be pushed inthe vertical direction by the flat band spring 90 acting on thelowermost positioned plunger rod follower 98 in the magazine 86. Whenthe following plunger rod segments 74 are pushed upwards in the verticaldirection, they are connected to a previous plunger rod segment in thatthe ledges 82 of the nose 80 of the subsequent segment fit into thegrooves 78 of the cut-out 76 of the previous segment and in that theplunger rod segments are inter-locked by the flexible tongues 84. Inthis manner a sequentially “building” of a continuous plunger rod 66 isperformed with the segments while performing injection of medicamentfrom the medicament container 70 through the injection needle 184 viathe tube 186.

Pausing of the Injection

The user may pause the injection by pressing shortly at both activationbuttons 20. This will cause the pin 160 of the pausing mechanism to bemoved from position IV in FIG. 16 to position V and along the inclinedsurface to position VI, causing the body 162 to move further upwards inthe slit 164. When the user releases the activation buttons, the spring149 between the cylindrical body 142 and the tubular body 144 will forcethe buttons outwardly to the initial start position while the pin 160also is moved back to the start position I along the walls of the grooveas seen in FIG. 16. The return of the activation buttons to theirinitial positions will in turn bring the locking element 258 inengagement with the indentations 256 of the regulator wheel 252 suchthat the rotation of the regulator wheel 252 is stopped. This in turnstops the spring housing 40 from rotation via the transmission, wherebythe injection is stopped.

The user may then resume the injection by pressing again on theactivation buttons 20 a, b, whereby the locking element 258 is moved outof contact with the regulator wheel, and the sequence continues in thesame manner as described above.

Auto-Stop Function

As described earlier, the second arm 268 b of the auto-stop mechanism260 is resting against the plunger rod segments 74 in the magazine.However, when the injection sequence is about to end when the medicamentcontainer has been emptied, there will be a space under the plunger rodfollower 98, which has been moved upwards during the “building” of theplunger rod. Thus the second arm 268 b is moved out of contact and theforce of the torsion spring 270 will cause the beam 262 to turn aroundits shaft 264, whereby the first arm 268 a will act on the ledge 206 ofthe needle cover 188, FIG. 24. This will in turn cause the needle cover208 to be turned around its longitudinal axis, which coincides with theproximal-distal axis 14.

The turning of the needle cover 188 will further cause the arms 180 ofthe needle holder 182 to be moved from the first part 204 a of the slitto the third part 204 c of the slit via the second part 204 b, FIGS. 12and 25. The turning of the needle cover 188 will cause the ribs 190 onthe outer surface of the needle cover to be aligned with the cut-outs196, FIG. 24 and due to the force of the needle cover spring 211 theneedle cover 188 is urged in the proximal direction. When now the deviceis removed from the body of the patient, the needle cover 188 willextend and surround the needle cover 188, FIG. 26. The movement of theneedle cover 188 is stopped when the ledges 206 come in contact with theinner surface of the proximal housing part 10. When in this position,the ledges 210 of the arms 208 on the inner surface of the proximalhousing part 10 will engage the distal end surface of the needle cover188, preventing any movement of the needle cover 188 in the distaldirection, thus locking the needle cover 188 in relation to the housingand the injection needle. Further, one of the ledges 206 is moved incontact with the teeth of the escapement wheel 240, FIG. 27, therebypreventing any further action or movement of the injection speed controlmechanism 212, should a user be pressing on the activation buttons. Thusthe device is locked and ready to be discarded.

Manual Stop Function

Instead of the automatic stopping of the device, it may be stoppedmanually by a user. This is done by pressing the actuator element 278upwards on the distal side of the device. This causes the arm 282 toslide vertically upwards, whereby the beam 286 is also moved upwards.This upwards movement of the beam will cause the needle cover 188 torotate due to the contact between the beam 286 and the ledge 207, whichrotation performs exactly the same functional sequence as with theautomatic stop function, FIG. 28. Thus the needle cover 188 will beextended and locked in the extended position and the injection speedcontrol mechanism 212 will be locked by the interaction of the ledge 206with the escapement wheel 240. The device may now be removed anddiscarded.

It is to be understood that the embodiment described above and shown inthe drawings is to be regarded only as a non-limiting example of theinvention and that it may be modified in many ways within the scope ofthe patent claims.

1. A medicament delivery device, comprising: a housing; a compartment inthe housing for positioning a medicament container; an injection needlehaving a proximal end and movably arranged within the housing andconnectable to the medicament container for supplying a dose ofmedicament; an activation mechanism comprising a button for activatingthe medicament delivery device; an actuation mechanism operablyconnected to the activation mechanism; a plunger rod positioned withinthe housing that operatively engages the medicament container duringdelivery of the dose of medicament, where the plunger rod moves in adirection transverse to the movement of the proximal end of theinjection needle; a driver operatively connected the actuation mechanismto move the plunger rod to cause delivery of the dose of medicament; anda needle cover having a central passage, where the proximal end of theinjection needle moves relative to and through the central passage,where delivery of the dose of medicament occurs through the injectionneedle and where both the needle cover and the central passage move in aproximal direction relative to the proximal end of the injection needlewhen the housing is moved away from a medicament delivery site.
 2. Themedicament delivery device of claim 1, where the movement of the centralpassage in the proximal direction is caused by a spring operativelyconnected to the needle cover.
 3. The medicament delivery device ofclaim 1, where a proximal end of the needle cover is arranged adjacentthe housing before and during delivery of the dose of medicament.
 4. Themedicament delivery device of claim 3, where the proximal end of theneedle cover moves to an extended position away from the housing whenthe injection needle during the delivery of the dose of medicament. 5.The medicament delivery device of claim 1, where the needle covershields the proximal end of the injection needle to preventunintentional needle sticks when the injection needle is moved away froma medicament delivery site.
 6. The medicament delivery device of claim1, further comprising an injection speed control mechanism operativelyconnected to the driver.
 7. The medicament delivery device of claim 6,where the speed control mechanism comprises gears.
 8. The medicamentdelivery device of claim 1, further comprising a medicament containerpenetration mechanism operably connected to the activation mechanism andconfigured to cause, upon activation, a fluid communication betweenmedicament inside the medicament container and the injection needle. 9.The medicament delivery device of claim 1, wherein the plunger rodcomprises a number of segments that are operatively connected to eachother.